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Ephoton
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Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.
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HgS will eventualy be converted to mercury and sulfur in the enviroment.
it is also a shit paint it faids and no one will supply vermillion in its true sence
other than one german paint manufacturer (well to my knowlage).
all of the vermillion that is sold were I live is an organic compound  .
e3500 console login: root
bash-2.05#
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JohnWW
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If they are selling a purely organic compound, or paint containing only it as the pigment, as "vermillion", when it does not contain any HgS, they
would surely be committing an offense under consumer-protection legislation.
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not_important
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| Quote: | Originally posted by JohnWW
If they are selling a purely organic compound, or paint containing only it as the pigment, as "vermillion", when it does not contain any HgS, they
would surely be committing an offense under consumer-protection legislation. |
Vermilion, like ultramarine, is a colour name as well as a substance. For some tine vermilion paint was likely a cadmium selenosulfide rather than
mercury sulfide, because thee cadmium pigment is more stable. More recently the toxicity of cadmium has lead to other pigments being used to product
the vermilion colour, this may or may not be labeled in a way that makes it easy to tell if it contains mercury or cadmium, the price may be as good
of an indicator as the label.
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S.C. Wack
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I cannot imagine why Ephoton resurrected this thread after three years to post that. I challenge anyone to provide any evidence of the color of HgS
fading away, or decompose to mercury and sulfur without the aid of heat. I find it very difficult to believe. Would you believe that there is HgS not
only many millions of years old, but still quite red?
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not_important
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| Quote: | | Imaging secondary ion mass spectrometry (SIMS) is applied for the first time to paint cross sections with degraded vermilion (red mercury sulfide)
paint to cast new light on the well-known problem of its light-induced darkening. The static SIMS data are combined with light microscopic, electron
microscopic studies and energy-dispersive X-ray analysis to identify and localize the various reaction products. The spatial distribution of atomic
and molecular species in paint cross sections of the native vermilion and the reaction products leads to the formulation of a new hypothesis on the
reaction mechanism of the photodegradation of vermilion where two black and white reaction products are formed sequentially. Under the influence of
light, some of the vermilion (HgS) is converted into Hg(0) and S(0). In this process, the chlorine ions, present in the native vermilion, act as a
catalyst. We propose that the Hg(0) is deposited on the surface of the remaining HgS as elementary mercury nanoparticles, which turns the vermilion
black. Chloride, derived from an external source, is accumulating in the black phase. The metallic mercury and the remaining HgS react away with the
excess of chloride. Two intermediate products and a white end product, mercuric chloride (HgCl2), are formed. |
Anal. Chem., 77 (15), 4742 -4750, 2005. 10.1021/ac048158f
Analytical Imaging Studies Clarifying the Process of the Darkening of Vermilion in Paintings
Katrien Keune and Jaap J. Boon
Also see attached file.
| Quote: | How English and American Vermilion Should Be Mixed for Sign Work, so as to Insure Good Wear.
English vermilion (or quicksilver vermilion) is sulphide of mercury. and very easily affected by strong light, which in time will turn it very dark,
no matter how well protected by varnish. The pale shade will darken much more rapidly than the deep shade. There is no protection against that ; it is
in the nature of the material. American vermilion, or chrome red, is the basic chromate of lead, and while it is a good wearing pigment it soon loses
its original scarlet red color and turns to a dull brown on exposure to strong light. Good, durable outside varnish will protect both of these
vermilions from too rapid darkening, but cannot arrest the change for any great length of time. |
739 Paint Questions Answered
By National painters magazine
Published 1904
| Quote: | the Pre-Raphaelite painter William Holman Hunt wrote of problems he suffered on account of lead and vermilion mixtures:
It seems as tho' I were struggling against Fate, every day sometimes including Sundays I have been toiling every hour, and just as I have got my
task nearly completed the whole thing has fallen into disorder again. At last I have found out what has been the cause of this -- Roberson's tube of
Orange Vermilion which I used without suspicion because 25 years ago they sold this colour absolutely pure, is adulterated with 10 per cent of
villainy -- the greater part lead, which has blackened so rapidly that when it had got dry enough for the final glazings the flesh had got to such a
colour that I nearly went crazy with the idea that my eye sight had acommodated itself to what could only be thought right by a fool when he was
trying to delude himself. I have had the colour analysed and at the same time have taken the opportunity to have others investigated and find that the
fraudulent habit is exercised in many other cases.
letter to John Lucas Tupper, August 1875
And again:
...the fact that vermilion, which was the first colour suspected by me, was analysed and found to contain between 10 and 12 per cent of foreign
matter, principally lead; that this vermilion is on two of my trial canvases, and where mixed with flake white (lead white) it has turned to 'café au
lait colour'.
Editorial letter to The Times of London
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Note that pure vermilion was often mixed with white lead for creating skin tones; the darkening was fairly common due to reactions between HgS and the
basic lead carbonates. However straight vermilion also discoloured on occasion.
Attachment: darkening of vermilion in paintings.pdf (1.2MB)
This file has been downloaded 1232 times
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S.C. Wack
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Well I asked for decomposition and I got it, OK. But that isn't exactly what I'm looking for.
| Quote: | | In this process, the chlorine ions, present in the native vermilion, act as a catalyst. |
Native vermillion=cinnabar. The old books that I've read all say that cinnabar was not used as a pigment in the industrial era. Vermillion was a
synthetic product or at least sublimed.
I don't see how forming HgS as a waste management solution is affected by someone saying that cinnabar pigments break down on painted surfaces on
exposure to light and chlorine.
The darkening is well known and not the same as "faid"ing.
[Edited on 26-7-2008 by S.C. Wack]
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not_important
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You said selling paint labeled "vermilion" but containing no HgS was fraud. I replied that the term "vermilion" had for some time been used to
describe the paint colour, rather than the pigment makeup, and this was partially due to the stability problems with HgS in paints You questioned that
instability, I showed evidence that said instability was an actual occurrence. BTW, there is a darkening and also the halide catalysed greying, which
usually is preceded by darkening and which often ends up giving a shade of grey lighter in tone than the original pigment - lightening or fading. It
can happen even with synthetic HgS, being caused by environmental chlorides.
No where did I mention anything to do with waste disposal, my comment was in regards to labeling of paint (and a warning to those seeking HgS that
way, if there's no mercury warning on the label then it's likely the paint pigment is not HgS even though it's vermilion in hue).
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S.C. Wack
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| Quote: | Originally posted by not_important
You said selling paint labeled "vermilion" but containing no HgS was fraud. I replied that the term "vermilion" had for some time been used to
describe the paint colour, rather than the pigment makeup |
Oh? Mmm...I think not.
| Quote: | Originally posted by not_important
...and this was partially due to the stability problems with HgS in paints You questioned that instability, I showed evidence that said instability
was an actual occurrence. |
No, I questioned
| Quote: | Originally posted by Ephoton
HgS will eventualy be converted to mercury and sulfur in the enviroment.
it is also a shit paint it faids |
...since I am unaware of any conversion of HgS to Hg and S in the environment, and the paint has been known to darken, rather than fade.
| Quote: | Originally posted by not_important
No where did I mention anything to do with waste disposal |
"I don't see how forming HgS as a waste management solution is affected by someone saying that cinnabar pigments break down on painted surfaces on
exposure to light and chlorine." does not seem to me like I was implying that you did. This simple statement does not strike me as improper in any
way, since the pdf was provided as proof that HgS was instable, as you just said. Note the thread title.
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j_sum1
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I am developing an interest in Hg chemistry. (No reagents of my own as yet except for a tiny amount of elemental mercury.) At the school where I work
there is also a small amount of HgO. I am interested in demonstrating the thermal decomposition of HgO in the manner of Laviosier and Priestly. It
seems like an important experiment for both historical and chemistry reasons. There is obviously other chemistry to explore as well.
Before I delve in, I want to make sure that I am covering all of my bases in terms of dealing with toxicity and disposal. There are the obvious
principles of converting all waste to stable insoluble forms, working in a fume hood with a scrubber, using gloves, keeping volumes minimal and so
forth. But I am new to this element. I don't want to be careless here. I'd like to pick the brains of those who are more experienced here.
My thoughts so far:
Elemental mercury
The main hazard is the vapour given off -- both from the element itself and potentially anything that has touched the mercury. There are
environmental issues associated with disposal.
What is the best way to neutralise the impact of elemental Hg? -- I understand that powdered sulfur and powdered zinc are both appropriate for spills.
Given the choice between an insoluble ionic solid and a zinc amalgum, which is preferred? Are there other options?
What is the procedure for dealing with contaminated glassware gloves and other equipment that has been in contact with Hg? It is fortunate that
mercury beads well, but it is possible to get micro droplets that are hazardous.
Waste of soluble mercuric salt solutions
Adding carbonate to precipitate mercuric oxide seems all too convenient. Is this sufficient?
Bubbling H2S and precipitating the sulfide sounds like a better idea.
Adding zinc has again been suggested upthread. Is this as good an idea as the H2S? I can do zinc powder with a much increased surface area. Or does
the extra hassle of dealing with waste as a powder rather than a rod make this unworthwhile?
Again, what is the best procedure for treating gloves, glassware, stirrers and the like? For lead I am content to liberally spray everything with a
carbonate solution and either dispose (in the case of gloves) or rinse and filter the rinsings to be disposed of as a solid. Is this good enough?
Would it be better to put disposable gloves in a bag containing H2S and leave for a while before disposing?
Mercuric oxide
Since this is my likely start material for my first experiment, I should ask some specific questions here.
How should I deal with cleaning / disposing of a used spatula? What about spills in the fume-hood? What about any unreacted residue on glassware?
Thoughts and experience appreciated. I would like to get this right.
[edit] I have no intentions at this stage of dealing with organic mercury. But if you have advice here I am glad to receive it.
[Edited on 24-2-2015 by j_sum1]
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Dr.Bob
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Your school would likely have a cow if they knew what they had and what you wanted to do. I have known two companies cited and fined $10,000's for
waste water issues for having <1 ppm of mercury in their waste water. So the school would likely want to avoid that. I am not saying that
people could not safely dispose of mercury compounds, I think the HgS route would work well, and be stable, but I would also just evaporate any finale
solution and put the solids in the trash rather than dump down the drain, as some municipalities are being hounded by the EPA for mercury in their
waste water at PPB and PPT levels. Note that the EPA in NC was found to be above one forbidden waste water level at their own research building, so
it is very easy to exceed the "safe" levels that they have arbitrarily created. I still remember playing with it as a kid and pouring it into my
hands and spilling it all over back then... But that might not have been real wise, but I think PPT are not likely that bad. Organomercury
compounds ARE that bad, so stay away.
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j_sum1
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My school has undertaken an overhaul of old chemical stocks and is in the process of having a bunch of chemicals professionally disposed of. As part
of building a new lab, there is also a review of chemical storage and procedures.
We have two Hg chemicals still in stock. A couple of hundred grams of elemental mercury, and a small amount of mercuric oxide. There is no problem
retaining them in stock but the rationale for doing so is that they will be used for legitimate educational purposes. Duplicating Priestly and
Loviosier meets the brief and fits in with the curriculum. And I am keen to maximise educational opportunities for the students. There seems to be
little point in having a lot of interesting chemicals and equipment and never using them while trying vainly to keep students interested with lame
experiments dissolving salt and boiling water. With the resources we have at school I see no reason why we cannot do this and do it properly.
Obviously I need to plan this ahead of time and learn what I need to know. Part (and only part) of this process is asking those who have had some
experience in handling mercury compounds. It is one thing to read in abstract terms about cleaning up. It is quite another to have someone explain
what to do with disposable gloves.
I am not in the US so the laws and penalties you cite will not apply. Of course there are local equivalents and I have no intention of tipping toxic
heavy metals straight down the sink.
I have asked some specific questions and would really value the input of those with some experience.
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MrHomeScientist
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One thing to keep in mind when working with elemental mercury is its incredible density. Being a very heavy liquid, it can slam around in containers
if not handled gently and break glass (so I've heard). It also pours much differently than you'd expect, and tends to rush out pretty quickly.
I haven't worked with mercury compounds yet, but I did generate some Hg-waste when I cleaned my stock of the element using the 'filter paper with a
pinhole' trick. That stuff was double bagged and stored in a large tub with my acids. I plan to take it to the local landfill during their "waste
amnesty days" and see if they will take it. I suppose I could sprinkle some sulfur dust in the bag with it to help absorb vapors. I think making HgS
is probably the safest option if you don't have anywhere to take it.
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